What is the ruling on one who is ignorant of a Sharia ruling, such as tajweed in prayer? Does he have to repeat his prayer if he makes a mistake in it? What is the ruling on one who suffers from obsessive-compulsive disorder (waswas) in ablution, such as excessive use of water, the amount of water for wiping the head, and placing hands in a vessel after waking up? What is the ruling on one who repeats recitation in prayer or mispronounces some letters due to waswas? Is it permissible for him to lead people in prayer?

Your question indicates that you have been afflicted with waswas (obsessive whispering/doubts). The Shari'ah did not come with hardship and extremism. Wudu' (ablution) is easy and facilitated. Wetting the hands and wiping the head is sufficient; there is no need for excessive effort in that, and do not try to keep one hand away from the other when washing them after sleep. Prayer is easy and facilitated. Allah has made the pronunciation of the Qur’an easy. Tajweed (rules of recitation) is obligatory, but omitting tafkheem (emphasis), tarqeeq (lightening), and idgham (merging) does not invalidate the prayer. So, fear Allah and do not open a door of evil for yourself.